84 



ANATOMY 



The number thus obtained was multiplied by the number of 

 times the unit volume was contained in the volume of the entire 

 cortex. The. final numbers computed for each of the nineteen 

 brain weight groups made it possible to determine when the 

 number of cells in the cortex was complete, but in the nature of 



TABLE 47 



Showing the average (corrected) thickness of the cerebral cortex in the albino rat 



by brain weight groups 



the case, these numbers, based on two layers only, have a rela- 

 tive rather than an absolute value. The results are given in 

 table 48. 



It appears from table 48 that when the computation is based 

 on the selected laminae, the number of cells in the cortex is 

 complete at about 20 days, or the time of weaning. 



